Polymers include natural and synthetic substances composed of very large molecules called macromolecules that are multiples of simpler chemical units called monomers. Polymers make up many of the materials in living organisms, including, for example, proteins, cellulose, nucleic acids, natural rubber and silk. Polymers may be synthesized in a laboratory, and such synthetic polymers have led to such commercially important products as plastics, synthetic fibers, and synthetic rubber.
Synthetic polymers are well known. For example, in 1931 the manufacture of neoprene, a synthetic rubber, began. Nylon is a synthetic thermoplastic material introduced in 1938. In order to improve various properties of synthetic polymers, additive materials are incorporated therein. Additive materials may improve properties such as strength, stiffness/rigidity, dimensional stability, appearance, and the like, as well as lower costs associated with making the synthetic polymers.
One concern associated with incorporating additive materials into synthetic polymers is that while some properties are improved, other properties are often compromised. One example is improving the strength of nylon by adding glass fibers thereto. However, when inorganic fillers are added to polyamides such as nylon without pretreatment, satisfactory properties cannot be obtained because of the poor affinity of the inorganic fillers for the polyamides. The poor affinity results in nylon products that are brittle and of low commercial value. Accordingly, selecting any given additive material for incorporation into a synthetic polymer necessarily means that certain polymer properties may be detrimentally affected. Moreover, it is often difficult to predict whether any given additive material will have a positive or negative effect on each polymer property. Such poor predictability is exacerbated by the fact that different additive materials effect polymer properties differently depending not only on the identity of the polymer, but also on such external factors such as temperature, radiation, and so forth.